ISO2002ENTMF 

Appendix C - Defined Conditions

A defined condition expression tests if a compilation variable is currently defined.

General Format

Syntax Rules

  1. An IS DEFINED condition evaluates as TRUE if compilation-variable-name-1 is defined.
  2. If compilation-variable-1 was defined via a DEFINE Compiler option, but preceding the defined condition in the program there is neither a corresponding DEFINE directive with the AS PARAMETER phrase nor a DEFINE directive without the OFF phrase for the compilation variable, then the defined condition for the compilation variable evaluates to FALSE.
  3. An IS NOT DEFINED condition evaluates as TRUE if compilation-variable-name-1 is not defined.
  4. If the most recent definition of compilation-variable-name-1 is via a DEFINE directive with the OFF phrase, it is considered to be not defined.